The investors also identified two people from a finance company in the same building as the law firm. The two people attended meetings and represented themselves as Rothstein's agent and broker, investors said.

Rothstein sold investors structured legal settlements in sexual harassment and whistle-blower cases that guaranteed a minimum 20 percent return, according to records he gave investors. The plaintiff would receive a discounted lump-sum payment from the investors, who would then collect the full settlement from Rothstein over several months.

Prosecutors now say the settlements never existed, and Gillies said Thursday that the alleged fraud could exceed $1 billion. No one, including Rothstein, has been charged.

"As the investigation proceeds, I believe that's where the evidence will take us," he said.

Rothstein's partner, Stuart Rosenfeldt, has said he had "no clue" about the alleged fraud. The other partner, Russell Adler, is blameless and "totally without any liability," said his lawyer, Fred Haddad.

Here's a look at some of those who participated in some way in Rothstein's investments, according to investors. It's not clear whether they knew about any fraud or were duped along with investors:

David Boden, general counsel of the law firm, sat in on Rothstein's meetings with investors and represented him in follow-up calls and negotiations.

Potential investor Alan Sakowitz, a Miami lawyer, met with Boden and Rothstein three times and said Boden tried to dispel his doubts in an August phone call.

"I asked him, 'Is this for real?' He said it was, that it's a legitimate deal, that everything was aboveboard," Sakowitz said.

Another group of investors met with Boden about the same time, and he gave them his law firm business card, said their attorney, Daniel Serber, of Aventura.

"David Boden was the contact person," Serber said. "He was the attorney who was in charge of negotiating the structured settlement documents."

After investors did not receive their scheduled payments from Rothstein the last week in October, Serber visited the law firm the Friday before Halloween. Rothstein already had left the country, and Boden met with Serber.

Boden told him that "it's business as usual" and that Rothstein had gone to London and "was working on getting some issues resolved so that the payments could be made."

Rothstein himself sent an e-mail later that afternoon, saying he was in London and would "instruct the wires to be sent out on Monday," Serber said.

Rothstein actually had flown to Morocco that Tuesday, and the payments never arrived.

Boden, 48, could not be reached despite several messages. He is cooperating with federal authorities, said his attorney, David Vinikoor.

"No one has advised us that he is" a target of the investigation, Vinikoor said. "I am viewing David Boden as a witness."

Records show Boden had been living in a $1.9 million Las Olas Isles home owned by a Rothstein corporation in recent months. He registered an Audi A4 there in August and listed that address on his driver's license.

Debra Villegas, the firm's chief operating officer, had an office in Rothstein's secured suite that was raided by federal agents last week, a day after Rothstein's return from Morocco.

Villegas' signature also appears on some of Rothstein's land transactions as a notary or witness.

Villegas, 42, worked her way up from paralegal to the chief executive of the 150-employee firm.

Federal prosecutors said Rothstein began running a Ponzi scheme in 2005. That year, Villegas earned $80,000 a year, according to her divorce records. Two years later, her salary had increased to $145,000.

In her 2007 divorce, Villegas reported receiving two high-end Swiss watches — a Rolex and a Breitling — from her "employer" and said Rothstein paid off her couch and a bedroom set and held title to her two Honda water scooters.

Villegas was living in a $475,000 Weston home that Rothstein signed over to her in July for $100 and "love and affection," according to the deed. Villegas registered a 2009 Maserati GranTurismo worth about $100,000 at the home in January.

Federal prosecutors took action this week to seize the home, alleging it was among Rothstein's ill-gotten assets.

Villegas could not be reached despite several messages. Her attorney, Paul Lazarus, declined to comment on whether she had a role in Rothstein's investment business.

"It's a matter the feds have under investigation," Lazarus said. "I have no comment."

When Serber visited the firm Oct. 30 to demand the overdue payments to the investors he represented, Boden produced e-mail messages from "the person who was in charge of the wire transfers, Irene Stay," Serber said.

Federal agents last week seized documents from Stay's office, including investment deposit logs and "emails from Rothstein to Irene to move money."

Stay, 45, could not be reached despite messages left at her office and home in Miami.

Richard Pearson, 52, president of a company that has offices in the same building as the law firm, told investors he was brokering the settlements for Rothstein.

"My clients were told that he was a broker and had the exclusive right to sell these investments," Serber said.

For one meeting, Serber's investors met Boden and Pearson in the law firm lobby and then went to Pearson's office at R.L. Pearson and Associates Inc., Serber said. A business card for Pearson's company says it is involved in commercial real estate, gaming and finance.

Sakowitz, the potential investor, said Pearson, representing himself as Rothstein's agent, wanted 20 percent of the profits from any investment his group made. He said Pearson sat in on his meetings with Rothstein.

Sakowitz said he learned of the investment opportunity from Nabil Rhazi, an associate in Pearson's company.

"Nabil was the one who reached out to my broker," he said.

Reached on his cell phone, Rhazi said he could not talk because he was at dinner and then did not respond to subsequent messages.

Martin Steinberg, an attorney for Pearson, said it was "too preliminary to tell anything."

"I never heard that before that Mr. Pearson was an exclusive agent for anybody," Steinberg said.

"TD Bank's internal bank records verified the amounts of money in the accounts and certified that they were held in trust for the benefit of investors," said William Scherer, an attorney representing investors who lost about $98 million.

Letters with Spinosa's signature certified the account balances and helped reassure investors that their money was safe, Scherer said.

"It would never have happened but for the bank," Scherer said.

Spinosa, 48, is on leave from the bank, pending an internal investigation. His attorney, Sam Rabin, described him as a "good and honorable man" who did nothing illegal.